The conservative lawmaker was first elected to the House in the 1994 Republican wave. He moved up to the Senate after a rough 2002 campaign in which he defeated Democratic incumbent Max Cleland, a triple amputee from his Vietnam war service.

Chambliss has been a GOP loyalist throughout his career, but he drew criticism from tea party Republicans for his participation in a bipartisan Senate "Gang of Six" focusing on the budget. The group advocated a mix of tax increases and spending cuts but failed to produce a bargain.

The state's senior senator had told 13WMAZ late last year that he was putting plans together for a third term in the Senate.

But he took criticism from some fellow Republicans when he said he would considering voting to raise taxes as part of a plan to avoid the federal "fiscal cliff."

Chambliss then voted for the New Year's Day package that included higher taxes for people making over $450,000.

But the tax issue apparently made Chambliss vulnerable to a more conservative primary challenger, according to a Public Policy Polling finding released in December.

The poll said 43 percent of usual Republican primary voters surveyed said they prefer someone more conservative than Chambliss.

There was no response from the senator's press office Friday morning.

The news immediately set off political speculation about the 2014 race.

The national Democratic Senatorial Campaign Committee also released this statement: "Georgia will now offer Democrats one of our best pick-up opportunities of the cycle. There are already several reports of the potential for a divisive primary that will push Republicans to the extreme right. Regardless, there's no question that the demographics of the state have changed and Democrats are gaining strength. This will be a top priority."

Chambliss's statement:

WASHINGTON -Today, U.S. Sen. Saxby Chambliss, R-Ga., released the following statement:

"After much contemplation and reflection, I have decided not to run for re-election to the Senate in 2014.

'This is a decision Julianne and I have thought through and prayed about for many weeks. I am humbled by and grateful for the extraordinary trust of Georgians, who have allowed me to represent them for 20 years in the United States House and Senate.

"I am proud of my conservative voting record in fulfilling those duties. In 2008, I was honored to receive more votes than any other statewide elected official in the history of Georgia. Lest anyone think this decision is about a primary challenge, I have no doubt that had I decided to be a candidate, I would have won re-election. In these difficult political times, I am fortunate to have actually broadened my support around the state and the nation due to the stances I have taken.

"Instead, this is about frustration, both at a lack of leadership from the White House and at the dearth of meaningful action from Congress, especially on issues that are the foundation of our nation's economic health. The debt-ceiling debacle of 2011 and the recent fiscal-cliff vote showed Congress at its worst and, sadly, I don't see the legislative gridlock and partisan posturing improving anytime soon. For our nation to be strong, for our country to prosper, we cannot continue to play politics with the American economy.

"I never intended to come to Washington and stay for 20 years. But in that time, I have been proud to fight for the economic good of Georgia and the security of our nation. That includes work on four farm bills, 18 defense-authorization bills, chairmanship of the House Terrorism Subcommittee in the wake of the 9/11 attacks, and being chairman or ranking member of major Senate committees for 8 of the past 10 years.

"Perhaps the greatest honor has been to champion our men and women in uniform, their families, and the Georgia military bases and contractors who create private-sector jobs.

"I am truly grateful for the love, support, trust and assistance of family and friends who have helped me along the way. I am especially indebted to my staff - past and present - whose loyalty and knowledge have not only served me well, but have served the people of Georgia superbly.

"There are two years left in my term, and there is lots left to do. I am in good health, and I plan to continue working hard to represent the best interests of Georgians, and to do my utmost to help restore America to its economic greatness."